The Wikibase registry was one of the outcomes of the first in a series of Federated wikibase workshops organised in partnership with the European research council.
The aim of the registry is to act as a central point for details of public Wikibase installs hosted around the web. Data held about the installs currently includes the URL for the home page, Query frontend URL and SPARQL API endpoint URL (if a query service exists).
During the workshop an initial data set was added, and this can be easily seen using the timeline view of the query service and a query that is explained within this post.
This is a belated post about the Wikibase docker images that I recently created for the Wikidata 5th birthday. You can find the various images on docker hub and matching Dockerfiles on github. These images combined allow you to quickly create docker containers for Wikibase backed by MySQL and with a SPARQL query service running alongside updating live from the Wikibase install.
A setup was demoed at the first Wikidatacon event in Berlin on the 29th of October 2017 and can be seen at roughly 41:10 in the demo of presents video which can be seen below.